کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
612772 | 880706 | 2007 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: How many phases and phase transitions do exist in Gibbs adsorption layers at the air–water interface? How many phases and phase transitions do exist in Gibbs adsorption layers at the air–water interface?](/preview/png/612772.png)
Four different phases and four different first-order phase transitions have been shown to exist in Gibbs adsorption layers of mixtures containing n-hexadecyl dihydrogen phosphate (n-HDP) and l-arginine (l-arg) at a molar ratio of 1:2. These conclusions have been made from surface pressure–time (π–t)(π–t) adsorption isotherms measured with a film balance and from monolayer morphology observed with a Brewster angle microscopy (BAM). The observed four phases are gas (G), liquid expanded (LE), liquid condensed (LC) and LC′LC′ phases. Three first-order phase transitions are G–LE, LE–LC and LC–LC′LC–LC′. However, the thermodynamically allowed G–LC phase transition in a 1.2×10−4M mixture at 2 °C, which is below the so-called triple point, is kinetically separated into the G–LE and LE–LC phase transitions. The most interesting observation is that the homogeneous LC phase shows a new first-order phase transition named as LC–LC′LC–LC′ at 2 or 5 °C. The LE and LC phases represent circular and fractal shaped domains, respectively, whereas the LC′LC′ phase shows very bright, anisotropic and characteristic shaped domains.
Different phase transitions observed in Gibbs adsorption layers at 2 °C.Figure optionsDownload as PowerPoint slide
Journal: Journal of Colloid and Interface Science - Volume 306, Issue 2, 15 February 2007, Pages 391–397